ID15B at ESRF for High-Pressure Experiments

The ID15B beamline at the European Synchrotron Radiation Facility (ESRF) was built four years ago, replacing its predecessor ID09A, in order to enable investigations of materials under extreme conditions.

Fast integration of a fast detector: the EIGER2 X CdTe 9M detector arrived at the ESRF in mid October, and it was put in use already in January 2021.

Although “extreme conditions” is a term that usually relates to studying minerals deep in the Earth’s mantle, the ID15B goes beyond that and offers its services to researchers who are working in various fields, such as fundamental physics, energy materials, catalysts, or chemistry. As this broad range of materials warrants different analytical techniques, the ID15B utilizes single-crystal X-ray diffraction, powder X-ray diffraction, and diffuse scattering over a range of pressures and temperatures.

After the ESRF-EBS upgrade, the beamline’s flux became approximately 15 times higher, and it started its operations in August 2020. The last step in the upgrade process was to commission a new detector. Installed in December 2020, the beamline’s EIGER2 X CdTe detector has already executed a number of tests and user experiments.

We sat down with Dr. Michael Hanfland, a scientist at the ID15B, and talked about the beamline and high-pressure experiments.

DECTRIS: The ID15B is mostly focused on high-pressure experiments. How did the experiments change after the ESRF-EBS upgrade?
Dr. Michael Hanfland, a scientist at the ID15B: When it comes to high-pressure experiments, the first thing to consider is that a sample gets thinner with increasing pressure. We perform our high-pressure experiments in a Diamond Anvil Cell (DAC) that allows pressures in the order of 100 GPa and above. At such pressures, the sample size is 10-30 microns, so the diffraction signal can be rather weak. This challenge has been solved through the combination of high flux and lenses, which allow us to focus the beam to 5 x 5 μm2. The other challenges include dealing with the background that arises from diffuse scattering of diamonds and covering all the X-ray diffraction that comes from the DAC.

DECTRIS: Your new detector, an EIGER2 X CdTe 9M, is smaller than your previous detector. How did this affect the data coverage that is attainable in a single shot?
Michael: When we thought about the detector, we wanted to strike a balance between the pixel size and the detector’s size. A smalldetector needs to get close to a DAC, and this often means that there is no place for an additional sample environment, like a cryostat. On the other hand, the larger the detector’s pixel size, the further away the detector can be placed from the sample.

With the EIGER2 X CdTe 9M, we reached this balance. In its default setup, the detector is placed 180 mm from the sample, but for in situor time-resolved measurements, it can be pulled back to 250-300 mm.



A zoom into the ID15B beamline at the ESRF: a setup for complex experiments at extreme conditions. Since the installation of the detector, the beamline has been conducting one experimentper week.

DECTRIS: How do the frame rates of 230 Hz fit your experiments, particularly in situ or time-resolved measurements?
Michael: So far, we have been running the detector at 5 frames per second, using an exposure time of 0.2 s. But, it is exciting to be able to achieve such high frame rates: for example, for collecting data in a continuous mode. This is something that we could not do before, but we know that a very fast, continuous scan can be beneficial for some applications: for example, very fast pressure changes.

Our other interests include incommensurate structures and charge density measurements. So, here, the high dynamic range of the 9M detector plays a more important role than the speed.

DECTRIS: Since the installation of the detector, you have performed many experiments and published one paper. How was this possible?
Michael: The whole process relied on good teamwork across different groups. The detector came in mid-October, and then the detector group at the ESRF tested it for a month. We installed the system at the beginning of November, and the user experiments started after the winter shutdown in January. For us, it was helpful that the ID11 (ESRF) beamline did the detector characterization, so we could immediately focus on the experiments we wanted to perform on the beamline.

On average, we are conducting one experiment per week. This is usually powder X-ray diffraction or single-crystal diffraction under various pressures and temperatures. Users either come to the beamline or conduct the experiments remotely (due to the COVID restrictions). As usual, we have had lots of experiments in the field of earth science, but also in fundamental physics, new materials produced by annealing, hydrogen storage materials, and superconductors.

And, indeed, Davide Comboni, a postdoc in our group, has been collaborating with a group of people on high-pressure synthesis of orthocarbonate Sr2CO4, and they have recently published their results. This publication was followed by another paper from users at the University of Montpellier.

DECTRIS: What is the outlook for the ID15B, and for high-pressure experiments in general?
Michael: Looking at the materials that are investigated, there is an increased interest in alkali metals and hydrogen, but also in organic materials, such as ferrocenes and benzene. From the experimental side, we see users’ interest in performing experiments at very high pressures, using continuous scans for data collection, and carrying out time-resolved experiments. We are happy to say that the ID15B is very well-equipped to support users and their current and future needs.

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